Exploring Cosmological Constraints of the Void-lensing Cross Correlation in the CSST Photometric Survey

Abstract We investigate the cosmological constraints from the void-lensing cross correlation assuming the w CDM model for the Chinese Space Station Survey Telescope (CSST) photometric survey. Using Jiutian simulations, we construct a mock galaxy catalog to z = 3 covering 100 deg 2 , which incorporates the instrumental and observational effects of the CSST. We divide the galaxy sample into seven photometric-redshift (photo- z ) tomographic bins and identify two-dimensional voids within each bin using the Voronoi tessellation and watershed algorithm. We measure the angular cross-power spectrum between the void distribution and the weak lensing signal, and estimate the covariance matrix via jackknife resampling combined with the pseudo- C ℓ approach to account for the partial sky correction. We employ the Halo Void Dust Model to model the void-matter cross-power spectrum and adopt the Markov Chain Monte Carlo technique to implement the constraints on the cosmological and void parameters. We find that our method can accurately extract the cosmological information, and the constraint accuracies of some cosmological parameters from the void-lensing analysis are comparable to or even better than the weak-lensing-only case. This demonstrates that the void lensing serves as an effective cosmological probe and a valuable complement to galaxy photometric surveys, particularly for the Stage IV surveys targeting the high-redshift Universe.